Remarks: This plant is presently known only from several widely separated populations. In contrast to other species of Scrophularia, which are insect pollinated, S. macrantha is pollinated by hummingbirds (Lightfoot and Sivinski 1994). This plant is now in the garden trade under the name redbirds-in-a-tree.

Conservation Considerations: Mining activities in Chino Pit at the Kneeling Nun outcrop will probably impact portions of that population. Other potential threats are wildfire, unregulated mining, road maintenance & construction. Many of the known sites in the Black Range burned in the 2013 Silver Fire. Although plants survived the immediate impacts of the fire, persistence is questionable in severely altered habitats.